Very little, except to a specific collector. The lenses I think you are referring to are "Pantar" front elements that attach to the Contina IIa with the Pantar 45mm replacable front element (it has a small tab at the bottom of the lens and a coin-knurled edge to the base lens). Three element, not great performance (I have the set). Fun to play with. Not a rangefinder.
Since they are front elements only, they are not useful on any other camera, except they also work on one of the early Zeiss Ikon SLRs, I forget which one. Not the ones that take the "Pro Tessar" lenses, which was a similar exercise, but with Tessar designs. That's all they're good for, I'm afraid.